A function of a transport network is to transport a service for a user. The transport network may use multiple transport technologies, such as a synchronous digital hierarchy (SDH), an optical transport network (OTN), and wavelength division multiplexing (WDM). A conventional transport network is a static system, and path creation, maintenance, removing and the like in the network all need to be configured manually by using a network management system. With an increasing growth of data services, such a connection manner cannot satisfy dynamic and flexible requirements imposed by a user on an optical network system. Therefore, the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) puts forward an automatically switched optical network (ASON) architecture. In the architecture, a control plane is added to a conventional optical network, to implement a function of automatically controlling the optical network. Then, the Internet Engineering Task Force (IETF) defines, based on the control plane, a generalized multi-protocol label switching (GMPLS) protocol stack, which implements functions such as automatic link discovery, path calculation and automatic path establishment in a network by executing protocols related to link management, routing, signaling, and the like.
In the prior art, distributed GMPLS is used to control a transport network. Each node runs a routing protocol such as Open Shortest Path First-Traffic Engineering (OSPF-TE), and a signaling protocol such as Resource Reservation Protocol-Traffic Engineering (RSVP-TE) to implement control over the transport network. However, once an operator needs to upgrade control functions of nodes in a network (for example, upgrading for using a new routing algorithm, or upgrading for supporting automatic control over optical power), control planes (including a routing module, a signaling module, and the like) of all nodes in the entire network need to be upgraded, so that an upgrading process is rather complex, is likely to fail, and has a high risk.